In case you are one of the unlucky guys who is currently facing iPhone battery drain and hotness problem after your iOS 4.2.1 firmware on 06.1.5.00 unlocked with Ultrasn0w 2.1, then the latest release of Redsn0w 0.9.6b6 will help you out. The release comes out with SAM (Subscriber Artificial Module) support, it is a module who is recently released by iPhone hacker Sam Bingner.
SAM will make your iPhone activated without neither hacktivation or using the original SIM card. Therefore, as the effect it will avoid the negative effect after your iDevices is hacktivated using PwnageTool (while jailbreak your iPhone) which causing the fast drainage to your iPhone battery.

Unfortunately SAM can ONLY be used to iPhone not other devices, such as iPod touch or iPad. And it's announced openly on the SAM website:

This is pointless on anything but an iPhone

Needless to say more, you can further continue to download the newly-released of Redsn0w 0.9.6b6 from the below links based on your used platforms: